Recently, an electric device and an electronic device have rapidly become compact and have higher-performances. Thus, it is required in the electronic components used in said devices to improve various characteristic (a specific permittivity, and a temperature characteristics or so) while sufficiently maintaining a reliability. A ceramic capacitor as an example of the electronic components is not exception.
As the dielectric material, particularly as for the dielectric material having high specific permittivity, a tetragonal barium titanate was mainly used, and a tetragonal barium titanate including a cubic was used partially. Also, recently in order to further improve the capacity, the dielectric layer is made thinner. In order to make the dielectric layer thinner, it is preferable to have smaller particle diameter of the dielectric particle. However, when the tetragonal barium titanate powder such as mentioned in the above is pulverized, there were problems such that the specific permittivity becomes low.
As the material having high specific permittivity, the hexagonal baium titanate is being considered. The hexagonal barium titanate, in nature, has lower specific permittivity than the cubic barium titanate, however in the Patent document 1, it is described that by introducing the oxygen defect in to the hexagonal barium titanate singlecrystal, the specific permittivity can be improved significantly.
However when the present inventors started the examination based on the teaching of the above Patent document 1, even though the specific permittivity was improved by introducing the oxygen defect, it was confirmed that the dielectric resistance declines. Thus, when using the hexagonal barium titanate having a improved specific permittivity by the introduction of the oxygen defect, the element lifetime may be deteriorated.
Also, as the structure of barium titanate, the hexagonal structure is a metastable phase, and usually it can exist only at 1460° C. or above. Therefore, in order to obtain the hexagonal barium titanate under room temperature, it is necessary to rapidly cool from the high temperature of 1460° C. or above.
In such case, by rapidly cooling from the high temperature, the specific surface area of the obtained hexagonal barium titanate becomes 1 m2/g or less, and only the rough powder can be obtained. When the electronic component comprising the dielectric layer which is made thin by using such rough powder is produced, it can not manage to make the dielectric layer thinner, and thus the reliability can not ensured sufficiently.
As for the producing method of the hexagonal barium titanate, for example, the non-patent literature 1 and 2 disclose to use BaCO3, TiO2 and Mn3O4 (non-patent literature 1) or oxide of Ga (non-patent document 2) as the starting source material, followed by heat treating.
However, the specific surface area of the hexagonal barium titanate obtained in the non-patent literature 1 is approximately 1.6 m2/g or so, and in case of using this hexagonal barium titanate, it is insufficient to apply to a thinner dielectric layer in the electronic components even though using this hexagonal barium titanate powder. In case of the non-patent document 2, the specific surface area is not mentioned; however since the synthesis temperature is 1300° C. which is relatively high, the specific surface area is same or less than that of the non-patent literature 1. Also, the hexagonal barium titanate having further high specific permittivity is demanded.    [Patent document 1] Japanese Patent No. 3941871    [Non-patent literature 1] Properties of Hexagonal Ba(Ti1-x Mnx)O3    Ceramics: Effects of Sintering Temperature and Mn Content (Japanese Journal of Applied Physics, 2007, Vol. 46, No. 5A, 2978-2983)    [Non-patent literature 2] Crystal Engineering 5 (2002), 439-448